Subaqueous shrinkage cracks and early sediment fabrics preserved in Pleistocene calcareous concretions

Duck, R. W.

doi:10.1144/gsjgs.152.1.0151

Cited by 29 publications

(29 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Relatively straight or regular edges of internal voids have led to genetic interpretations centered on internal stress-induced (Astin 1986;SellesMartinez 1996;Hounslow 1997), synsedimentary earthquake-induced (Pratt 2001), and/or shrinkage (Duck 1995;Hendry et al 2006) cracking. Regardless of the specific reason for internal cracking, the superposition of cements seemingly provides a straightforward paragenetic sequence of cement precipitation.…”

Section: Introductionmentioning

confidence: 99%

Clumped-Isotope Constraints On Cement Paragenesis In Septarian Concretions

Loyd¹,

Dickson²,

Boles³

et al. 2014

Journal of Sedimentary Research

View full text Add to dashboard Cite

Septarian concretions exhibit multiple generations of cements that include body, fringe, and spar phases. Classic paragenetic interpretations include initial precipitation of the body followed by fringe(s) and then by spar in more or less discrete events. Traditional approaches (e.g., carbon and oxygen isotope analyses) are generally unable to distinguish paragenetic trends as they relate to specific formation environments (e.g., precipitation during burial or with meteoric influx O fluid compositions of , 214 to +4% (VSMOW). In stable-isotope cross-plots, specific cement phases group together and confirm the paragenesis indicated by superposition. In some cases, samples analyzed from concretion bodies yield temperature and d18 O fluid values that indicate formation at shallow depths, consistent with independent data (e.g., high minus-cement porosity, external laminae deflection). In contrast, other concretion-body analyses indicate relatively high body temperatures that conflict with shallow-formation indices. Petrographic and backscatter scanning electron microscopy (SEM) reveal that concretion bodies partially consist of a secondary, replacement phase, which could explain the higher temperatures expressed in bulk body samples. Based on data for different phases in these septarian concretions, we suggest that initial body-cement precipitation occurred at relatively shallow depths from unmodified seawater, followed by fringe formation at elevated temperatures that likely coincided with the emplacement of the secondary body phase. When considered together, late-stage spar phases exhibit temperatures and d18 O fluid values supportive of spar precipitation from fluids with a significant meteoric component, possibly during uplift.

show abstract

Section: Introductionmentioning

confidence: 99%

Clumped-Isotope Constraints On Cement Paragenesis In Septarian Concretions

Loyd¹,

Dickson²,

Boles³

et al. 2014

Journal of Sedimentary Research

View full text Add to dashboard Cite

show abstract

“…Some authors suggest that concretions commonly form during early burial at or just below the sediment-water interface, sometimes during single precipitation episodes (Hudson 1978;Carpenter et al 1988;Mozley and Burns 1993;Duck 1995;Middleton and Nelson 1996;Raiswell and Fisher 2000;Woo and Khim 2006). These shallow-burial concretions can preserve aspects of the original groundwater chemistry and depositional sedimentary fabric (Canfield and Raiswell 1991;Mozley and Burns 1993;El Albani et al 2001;Roberts and Chan 2010;Dale et al 2014), which can be useful for interpreting environments of deposition at sites where facies analysis is otherwise difficult because of limited or no exposed host rock.…”

mentioning

confidence: 99%

Depositional Environment of the Lower Cretaceous (Upper Albian) Winton Formation At Isisford, Central-West Queensland, Australia, Inferred From Sandstone Concretions

Syme¹,

Welsh²,

Roberts³

et al. 2016

Journal of Sedimentary Research

View full text Add to dashboard Cite

Numerous vertebrate and plant fossils have been found in ex-situ sandstone concretions near Isisford in central-west Queensland since the mid-1990s. These concretions are found in the Lower Cretaceous portion (upper Albian, 100.5-102.2 Ma) of the Winton Formation. The lower most Winton Formation is thought to have formed in a fluvial channel or flood-basin setting proximal to the Eromanga Sea, but due to the scarcity of good exposures, the local depositional environment at Isisford has not been ascertained. Minimal compression of vertebrate and plant fossils, a lack of grain suturing, predominantly cement-supported fabric, and fractures running through calcite cement, as well as fossil bone and framework grains, indicates that concretions formed during early diagenesis (pre-compactional or syndepositional). Calcite stable-isotope δ 18 O VPDB values range from -12.25 to -4‰, indicating mixed marine and meteoric pore waters, and δ 13 C VPDB values range from -5.3 to 4.1‰, indicative of both sulfate reduction and methanogenesis of organic material (including decaying vertebrate soft tissues) in the burial environment. The mixed marine and freshwater signature suggests a marginal marine setting, possibly deltaic or estuarine, connected to the regressive epicontinental Eromanga Seaway at around 102-100 Ma. This is not inconsistent with the lithology from nearby cores, coupled with Isisford fossil-vertebrate ecology (personal observation). Our research demonstrates the utility of investigating ex-situ concretions to refine paleoenvironments at localities where little or no outcrop is available and traditional facies analysis is impractical. INTRODUCTIONSandstone concretions cemented with calcium carbonate have been reported worldwide, ranging from the centimeter scale (Dix and Mullins 1987;Allison and Pye 1994;Mozley and Davis 2005; Tabor et al. 2007), the decimeter to meter scale (Dix and

show abstract

“…To date, various scenarios of septaria formation have been brought forward. Astin (1986) suggested that septarian cracks are the result of tensile stress caused by overpressure applied on the concretion and its host, Duck (1995) interpreted them as subaqueous shrinkage cracks generated by the conversion of a calcium "soap" of fatty acids to calcite, Sellés-Martínez (1996) suggested amplification of stress around a stiff concretion in a more plastic sediment, finally Hounslow (1997) suggested a scenario similar to that of Astin (1986) with the difference that he assumed higher pressure inside the concretion body than in the surrounding sediments. This higher pore pressure within the concretion body was suggested to be caused by permeability loss due to cementation of the concretion (Hounslow, 1997).…”

Section: Formation Of the Steinbrunn Septariamentioning

confidence: 98%

“…However, whereas concretions incorporate material of the host sediment, nodules contain solely authigenic phases. Concretions are usually spherical or ellipsoidal, but also come as elongated, oblate, tubular, lobate, or irregular bodies (Coleman and Raiswell, 1995;Duck, 1995;Thomka and Lewis, 2013). The authigenic phases of concretions that cement the background sediment are composed of carbonate, phosphate, silica, sulfide, sulfate, and iron oxide minerals (Coleman et al, 1985;Mozley, 1996;Yli-Hemminki et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

“…Most common parageneses are carbonate concretions in clayey or sandy horizons, quartz or chert in limestones, and pyrite in black shales (Coleman et al, 1985;Sellés-Martínez, 1996), and the most common concretion-forming minerals are carbonates such as calcite, Mg-calcite, Fe-calcite, siderite, and dolomite (Siegel et al, 1987;Pye et al, 1990;Mozley, 1996). Concretion size varies from millimeters to meters, and estimated growth rates vary from tens to hundreds up to thousands of years for decimeter-sized concretions (Duck, 1995;Pratt, 2001;Thomka and Lewis, 2013). The growth of concretions of meter size is assumed to take millions of years (Sellés-Martínez, 1996).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microbially-driven formation of Cenozoic siderite and calcite concretions from eastern Austria

Baumann¹,

Birgel²,

Wagreich³

et al. 2016

AJES

View full text Add to dashboard Cite

Carbonate concretions from two distinct settings have been studied for their petrography, carbon and oxygen stable isotope patterns, and lipid biomarker inventories. Siderite concretions are enclosed in a Paleocene-Eocene deep-marine succession with sandy to silty turbidites and marl layers from the Gosau Basin of Gams in northern Styria. Septarian calcite concretions of the southern Vienna Basin from the sandpit of Steinbrunn (Burgenland) are embedded in Upper Miocene brackish sediments, represented by calcareous sands, silts, and clays. Neither for the siderite, nor for the calcite concretions a petrographic, mineralogical, or stable isotope trend from the center to the margin of the concretions was observed, implying that the concretions grew pervasively. The δ 13 C values of the Gams siderite concretions (-11.1 to -7.5‰) point to microbial respiration of organic carbon and the δ 18 O values (-3.5 to +2.2‰) are in accordance with a marine depositional environment. The low δ 13 C values (-6.8 to -4.2‰) of the Steinbrunn calcite concretions most likely reflect a combination of bacterial organic matter oxidation and input of marine biodetrital carbonate. The corresponding δ18 O values (-8.8 to -7.9‰) agree with carbonate precipitation in a meteoric environment or fractionation in the course of bacterial sulfate reduction. Lipid biomarkers have been extracted before and after decalcification of the concretions in order to assess pristine signatures and to exclude secondary contamination. The siderite concretions did not yield indigenous biomarkers due to their high thermal maturity. The calcite concretions comprise abundant plant wax-derived long-chain n-alkanes, reflecting high terrestrial input. Bacterial-derived, terminally-branched fatty acids and hopanoids were found, but with overall low contents. The presence of framboidal pyrite, the moderately low δ 13 C values, and the biomarker inventory indicate that bacterial sulfate reduction contributed to the formation of the calcite concretions in a brackish environment. The low δ 13 C values of the siderite concretions, on the other hand, are best explained by bacterial iron reduction, since sulfate reduction and resultant hydrogen sulfide production would have inhibited siderite precipitation. This study documents a new example for an exception from the common pattern that siderite concretions preferentially precipitate in freshwater environments. The Gams siderite concretions formed within marine sediments, whereas the Steinbrunn calcite concretions formed in freshwater to brackish sediments. Karbonatkonkretionen aus verschiedenen Ablagerungsräumen wurden im

show abstract

Subaqueous shrinkage cracks and early sediment fabrics preserved in Pleistocene calcareous concretions

Cited by 29 publications

References 29 publications

Clumped-Isotope Constraints On Cement Paragenesis In Septarian Concretions

Clumped-Isotope Constraints On Cement Paragenesis In Septarian Concretions

Depositional Environment of the Lower Cretaceous (Upper Albian) Winton Formation At Isisford, Central-West Queensland, Australia, Inferred From Sandstone Concretions

Microbially-driven formation of Cenozoic siderite and calcite concretions from eastern Austria

Contact Info

Product

Resources

About